Space missions deliver treats from Saturn and beyond

Saturn and its rings glow in a backlit, enhanced-color image from the Cassini orbiter. The picture combines images that were acquired using infrared, red and violet filters on Oct. 17. Two of Saturn's moons, Enceladus and Tethys, sparkle on the left side of the planet.

The holiday season is bringing beautiful baubles from outer space, including an unconventional view of Saturn from the Cassini orbiter, a gaudy nebula from the Hubble Space Telescope and a loopy picture of a supernova's leftovers. You can even send your own celestial season's greetings.

The Saturn picture, released today, marks the first time Cassini captured a backlit view of the ringed planet since 2006. That earlier photo made a huge splash, in part because the planet Earth could just barely be seen as a pale blue dot off to the side. This time, Earth is hidden behind Saturn, but you can spot two moons just to the left and below the planet: The closer speck is Enceladus, and Tethys is farther down and to the left.

This isn't the view that human eyes would see: Cassini's wide-angle camera snagged this picture in infrared, red and violet wavelengths from a distance of 500,000 miles (800,000 kilometers) behind Saturn on Oct. 17. The various views were assigned different colors in the visible-light spectrum to produce this eerie, otherworldly picture. Here's what Carolyn Porco, leader of the Cassini imaging team at the Colorado-based Space Science Institute, says about the image in today's "Captain's Log":

"Of all the many glorious images we have received from Saturn, none are more strikingly unusual than those we have taken from Saturn's shadow. They unveil a rare splendor seldom seen anywhere else in our solar system.

"This one is our special gift to you, the people of the world, in this holiday season that brings to a close the year 2012. We fervently hope it serves as a reminder that we humans, though troubled and warlike, are also the dreamers, thinkers, and explorers inhabiting one achingly beautiful planet, yearning for the sublime, and capable of the magnificent. We hope it reminds you to protect our planet with all your might and cherish the life it so naturally sustains.

"From all of us on Cassini, the happiest of holidays to everyone."

The Hubble Space Telescope's science team is also rolling out the holiday goodies, with a twisty planetary nebula known as NGC 5189 serving as the centerpiece. "The intricate structure of this bright gaseous nebula resembles a glass-blown holiday ornament with a glowing ribbon entwined," the Hubble team says in today's photo advisory.

NASA / ESA / Hubble Heritage

A holiday image from the Hubble Space Telescope shows the planetary nebula NGC 5189. The image was captured by Hubble's Wide Field Camera 3 on Oct. 8.

Planetary nebulae like NGC 5189 are formed when a medium-sized star like our sun enters the last stages of its life, and puffs away its outer shells of glowing gas. This nebula's swirly structure is thought to be due to the influence of an unseen companion star that's stirring the pot, gravitationally speaking.

The picture was taken by Hubble's Wide Field Camera 3, one of the instruments that was installed during the telescope's final servicing mission in 2009. The camera's filters were tuned to the specific wavelengths of fluorescing sulfur, hydrogen and oxygen atoms, plus broad filters in visible and near-infrared wavelengths to capture the star colors.

The National Optical Astronomy Observatory and WIYN Consortium are also putting out a glittery end-of-the-year picture of the Cygnus Loop, a giant supernova remnant that glows 1,500 light-years away in the constellation Cygnus. The observations were made in 2003 by astronomer Richard Cool, using the NOAO Mosaic 1 camera on the WIYN 0.9-meter telescope on Kitt Peak, Ariz.

The Cygnus Loop shines in a picture released by the National Optical Astronomy Observatory and the WIYN Consortium.

Back then, the computing power wasn't sufficient to process the picture's 600 million pixels into a single, full-resolution color image. Now the telescope observations have been re-reduced and reprocessed by Travis Rector at the University of Alaska at Anchorage to produce the version released today. "Images like this are amazing, because they can remind you of the big picture and beauty that surrounds us," Cool said in NOAO's image advisory.

These pictures are cool enough for Christmas cards, but if you need a little inspiration for your last-minute mailing list, the teams behind NASA's Great Observatories can help: The Space Telescope Science Institute's Hubble Web site offers printable holiday cards. The team behind the Chandra X-Ray Observatory has e-cards suitable for a variety of occasions. You can turn to Zazzle or CafePress to order greeting cards featuring imagery from the Spitzer Space Telescope.